Accident Overview
On June 25, 2009, at 1500 Pacific daylight time, a Robinson R44 II helicopter, registration N515DG, experienced a hard landing during a forced landing approximately 7 miles west-northwest of Lakeport, California. The helicopter was operated by Cutting Edge Helicopters under 14 Code of Federal Regulations Part 91. The certified flight instructor (CFI) and the private pilot undergoing instruction (PUI) were not injured. The helicopter sustained substantial damage. Visual meteorological conditions prevailed, and no flight plan was filed.
Accident Sequence
According to the CFI, the helicopter had been fueled to capacity prior to takeoff. The pilots were conducting a 180-degree autorotation with power recovery. As they entered the helicopter into a glide and began the turn, the CFI observed that the oil and auxiliary fuel pump lights were illuminated. The CFI then checked the tachometer and attempted to increase the throttle. The power did not return, prompting the CFI to commit to a landing. During the landing, the main rotor blades struck the tail boom.
Post-Accident Examination
Following recovery from the accident site, the helicopter and engine were examined. The spark plugs were removed and inspected. Their condition was consistent with normal operation when compared to a Champion Check-A-Plug chart. With the engine still installed on the helicopter and using the original fuel onboard, the engine was powered and tested. The run found no pre-impact anomalies.
Relevant Safety Information
According to Robinson Helicopter Company Safety Notice SN-38, titled "Practice Autorotations Cause Many Training Accidents," it states: "There have been instances where the engine has quit during practice autorotation. To avoid inadvertent engine stoppage, do not roll the throttle to full idle. Reduce throttle firmly for a small visible needle split, then hold throttle firmly to override governor. Recover immediately if engine is rough or engine RPM continues to drop."